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Sunflower Redux Build

04-18-2018, 09:18 AM

Hi all,
My father is currently building his first set of speakers and decided to go with Paul Carmody's Sunflower Redux design. He is doing all of the woodwork and most of the fabrication overall. He decided to use MDF for the box/baffle, and solid cherry for the framing wood. I contributed a small bit by doing the box CAD/drawings/design work as well as the crossover layout and fabrication. We are both into audio but have never built speakers before. He hit me up sometime late last year and expressed an interest in making a set, so I said I'd help. Dad has the wood shop and hands-on expertise needed for a project like this. I have some familiarity with the basics of audio and am an engineer so I thought I might have or be able to learn the technical aspects of the project and help from that side. We figured between the two of us that we could probably do a good job on something like this. We live in different parts of the country which has presented some challenges for sure, but overall it has been a fun and interesting project that I think is turning out great. I thought I'd share some pictures on behalf of my Dad in case there was any interest.

This is my CAD mockup of the box design. It was used to get the aesthetic right for what my Dad wanted, as well as to make dimensioned drawings to send to him. Most of the basic information was already available on Paul's website as some other forum posts. I made some changes to overall shape and dimensions as well as coming up with a way to attach the cherry side panels to the MDF without having to worry about wood expansion causing issues later. Box volume was supposed to be 42L per Paul's notes, but I found that there was an error in the original write up and calculations which caused volume to actually be closer to 38L. Not a huge deal, but I corrected for it while I was at it. We also incorporated a removable back panel for easier access.

Here's another CAD mockup of the box with a cross section view. You can see the XO location, wiring strategy, bracing, and so on. I did the volume calculations based right off of the CAD so I could compensate for the volume of the bracing and other components inside the space without lengthy hand calculations.

This shot is from my Dad's shop across the country when he'd just started. He made a circle jig to cut the holes for the front baffle and got excellent results. He's a woodworking pro with a full shop, so this part of the project is right up his alley.

The drivers fit nice and flush with the front baffle, and the chamfers on the rear turned out well too!

Between rabbet and dado joints, biscuits, and copious amounts of glue, this whole thing will be rock solid. This picture shows the baffles again, but primed and with the dados and rabbets cut for the woofer box panels to attach to.

This was a dry fit up my Dad did--nothing is glued in place quite yet. The joints are spot on and everything fits very nicely.

This shot shows another dry fit up from the front. At this point it was starting to actually look like a speaker cabinet! You can see on the bottom portion of the baffle he installed the cherry veneer, and if you look closely you can also see a brace on the inside of the box.

Here's a closer view of the inside of the box with the bracing in place. The mortised slots on the walls are there to accommodate slot washers, Belleville washers, and some other hardware that will hold the cherry accent frames securely to the woofer box while still allowing for expansion and contraction over time.

Same sort of thing as the image above, with just a slightly different perspective.

These are the cherry frames I mentioned, while Dad was doing the glue up for them. The white piece is a jig that he made to cut all four of them identically using a router and a flushing cutting bit.

This is another dry fit up with one of the cherry pieces roughly in place. I believe he will paint all the MDF black, and will shellac the cherry along with another finish. After all that is done, the box will be glued together and the cherry pieces will be permanently attached.

As mentioned earlier, I helped out by doing the crossover layout and assembly work. This picture shows both crossovers just after I completed them. I am pretty happy with how they turned out, but definitely learned a few things that would be useful to know for the next time I do one.

Closeup of one of the crossovers again.

This is about as far as the project is so far, but I will try to keep things updated as the project progresses and my father finishes out the cabinet construction if there is enough interest. Thanks for looking!

Comment

Looking great, nice build quality.* If you can figure a way to design out the protruding lip around the drivers (presumably for a grill), I would do so, that's a significant diffraction source and will lower the performance of the design somewhat.* I like rounding edges too but if that doesn't work visually it's less of* an issue than the projecting lip. Sensitivity to diffraction varies, but if it can be largely designed out, it should ideally be.* * I'd also suggest adding some more bracing to the design, with the cost and effort you're putting in, it's an easy thing to do and should help limit any "chesty" coloration.*

Comment

Wow those look fantastic! I hope to have the funds to build these in the next few years...currently happy with my amiga towers but I know that once we move into a house with a dedicated theatre room, the sunflowers should be a nice upgrade - I've already built the center sunflower speaker and it pairs quite well with the amiga towers.

Will you be amplifying these or just running off of a receiver? I assume they would sound better with a dedicated amp - I wouldn't know quite how much power to feed them though!